Final answer:
Blood in the pulmonary veins is oxygenated as it returns from the lungs to the heart, ready to be distributed to the rest of the body.
Step-by-step explanation:
The pulmonary veins carry oxygenated blood. This means that the blood in the pulmonary veins has been through the lungs where it has picked up oxygen, thus being ready to supply oxygen to the tissues of the body. This is in contrast to deoxygenated blood, which is found in vessels like the inferior vena cava and the pulmonary artery, circulatory structures that carry blood back to the lungs for oxygenation.
Here's how it works in the circulatory system: Deoxygenated blood returns to the heart via the inferior vena cava, enters the right side of the heart, and is then pumped to the lungs via the pulmonary artery. After reaching the lungs, the blood becomes oxygenated during gas exchange and returns to the left side of the heart via the pulmonary veins. The newly oxygenated blood is then pumped out to the body through the aorta. Thus, the statement 'Blood in the pulmonary vein is deoxygenated.' is false.